Low-dose computed tomography (LDCT) images are often severely degraded by amplified mottle noise and streak artifacts. These artifacts are often hard to suppress without introducing tissue blurring effects. In this paper, we propose to process LDCT images using a novel image-domain algorithm called "artifact suppressed dictionary learning (ASDL)." In this ASDL method, orientation and scale information on artifacts is exploited to train artifact atoms, which are then combined with tissue feature atoms to build three discriminative dictionaries. The streak artifacts are cancelled via a discriminative sparse representation operation based on these dictionaries. Then, a general dictionary learning processing is applied to further reduce the noise and residual artifacts. Qualitative and quantitative evaluations on a large set of abdominal and mediastinum CT images are carried out and the results show that the proposed method can be efficiently applied in most current CT systems.

The ongoing outbreak of COVID-19 that began in Wuhan, China, become an emergency of international concern when thousands of people were infected around the world. This study reports a case simultaneously infected by SARS-Cov-2 and HIV, which showed a longer disease course and slower generation of specific antibodies. This case highlights that a co-infection of SARS-Cov-2 and HIV may severely impair the immune system.

No abstract

No abstract

No abstract